Process of preparing trinuclear cyanine dyes containing a terminal 5-membered nitrogenous heterocyclic ring system



Patented Aug. 15, 1930 PROCESS OF PREPARING TRINUCLEAR CYANINE DYES CONTAINING A TERMINAL -MEMBERED NITROGENOUS HETERO-" CYOLIC V RING SYSTEM Thomas R. Thompson, Binghamton, N. Y., as-

signor to General Aniline & Film Corporation,

New York, N. Y., a corporation of Delaware No Drawing. Application December 2 1, 1948, I

Serial No. 66,574

This invention relates to trinuclear cyanine dyes and to a method of preparing the same.

Trinuclear cyanine dyes have been prepared by the method described in'United States Patent 2,388,963. The method consists of first quaterv nizing a cyclammonium base containing a reactive thio group, and condensing it with a; 3- ethylrhodanine to obtain the merocyanine intermediate. This procedure involves two steps and requires about 4 hours time. 1 The merocyanine intermediate is then fused with a mixture of a cyclammonium base and a quaternizing agent, such as methyl p-toluenesulfonate for 2 to 3% hours. After cooling the melt, pyridine is added and the mixture reheated under reflux for 20 to 30 minutes. The reaction mixture is then poured into an aqueous solution of potassium bromide and the final dye obtained by recrystallization from alcohol. The minimum time required for the latter two steps is approximately from 3 to 4 hours, exclusive of the time required to cool the reaction mixture.

' Theoretically, the trinuclearfidyes should be capable of production by treating aB-alkylrho danine with an alkyl salt to effect quaternization of the hetero nitrogen atom thereof, and conversion of the thioketo group to a thioether I group, the reaction of the thioether group with the reactive grouping of a cyclammonium salt.

and the linking of the intermediate so formed to a cyanine dye intermediate through the reactive methylene group of the thiazolone ring. In other words, it would'seem that said dyes would form by carrying out, with the 3-alkylrhodanine per se, the last step of the conventional process and using the thus formed intermediate for reaction with another mol of a cyanine dye intermediate. Very surprisingly, however, it has been ascertained that the 2-alkylthio-3-alkylrhodanines do not react with a cyclammonium salt to yield thiazolone cyanine dye intermediates.

Because of this, the art has become firmly convinced that in order to prepare trinuclear cyanine dye'sof the rhodacarbocyanine type, it is necessary to treat a preformed merocyanine dye with an alkyl salt to simultaneously eiiect quaternization of the nitrogen atom of the rhodanine ring system and the conversion of the thio keto group to a thioether group, and to react the resulting salt with a cyclammonium quaternary salt of the typeused in the formatibn of cyanine dyes. The process steps involved in this preparation are not only tedious but time .con-

8 Claims. .(o1. 260240l1l 2 7 It is an object of the present invention to provide a new class of trinuclear cyanine dyes.

A further object of the present invention is a method of'producing the said dyes.

A still further object i to provide a simpler method whereby new trinuclear cyanine dyes in excellent yield are obtained.

Other objects and advantages will become apparent from the following description.

I have found that trinuclear cyanine dyes are obtained in excellent yield and in readily purifiable form by treating a 3-a1kyl, 3-aryl, or 3- aralkyl substituted 5-membered ketomethylene heterocyclic compound containing a reactive methylene group adjacent to a keto group of the type commonly employed in merocyanine dyes with a thiazolone cyanine dye salt intermediate in the presence or absence of a suitable solvent, such as an aliphatic alcohol, e. g., methyl, ethyl, n-propyl, isopropyl, and the like, and in the presence of a basic condensing agent, such as trimethylamine, triethylamine, pyridine, methylpyridine, ethylpyridine, quinoline, potassium carbonate and the like, on a steam bath or by heating the reaction mixture at reflux for a period of from 5 to 20 minutes.

The dyes obtained by the foregoing procedure are characterized by the following general formula:

n laz X wherein R represents hydrogen or an alkyl group, e. g., methyl, ethyl, propyl or butyl, B being only alkyl when m represents 1, R1 and R2 which may be alike or difierent represent, an alkyl, allyl, aryl, or aralkyl group, e. g., methyl, ethyl, propyl, phenyl, naphthyl, tolyl, benzyl, phenethyl and the like, R3 represents an aliphatic, aryl, aralkyl or substituted group of this type, e. g., methyl, ethyl, propyl, butyl, hydroxyethyl, ethoxyethyl, phenyl, tolyl, naphthyl, benzyl, phenethyl, menaphthyl and the like, m represents a positive integer of from 1 to 3, X represents an acid radical, e. g., chloride, bromide, iodide, or alkyl sulfate, alkyl p-toluenesulfonate or perchlorate, Y represents the residue of a 5- membered heterocyclic nitrogenous ring system zolediones, thiazolones, oxazolediones, thiohydantoins, and the like, and Z represents the residue of a heterocyclic nitrogenous nucleus of the type used in cyanine dyes, e. g., oxazoles, thiazoles, selen-azoles, and their polycyclic homologues, such as those of the benzene, naphthalene, acenaphthene, and anthracene series, pyridine, and its polycyclic homologues, such as quinoline and onand B-naphthaquinolines, perinaphthiazoles, indolenines, diazines, such as pyrimidines and quinazolines, diazoles (e. g., thio-fl-fi'-diazole), oxazolines, pyrrolines, thiazolines and selenazolines (the polycyclic. compounds of these series bein substituted if desired in the carbocyclic rings: with one. or more. l5 conventional groups, such as. alkyl or aryl, as below, amino, hydroxy, alkoxy, i. e., methoXy, ethoxy, etc., and methylene-dioxy groups, or by halogen atoms, i. e., chlorine, bromine, etc).

The N-substituted 5-membered ketomethylene heterocyclic compounds of the type commonly employed inmerocyanine dye. synthesis, which are: treatedv with a thiazolone cyanine. dye. intermediate are characterized by the following general, formula:

r -Y'- I'- l l b'l-C 041m .1; wherein Y and R1 have the same values as above.

As typical examples of such compounds, the

following maybe mentioned;

. 1,,3-diphenyl-5-pyrazolone 3-phenyl-2,4ethiazoledione 2-diphenylamino-3-ethyl-4(5) thiazolone 3-ethyl-2.-thio-2,4(,3,5)-oxazoledione 3 -eth-yl-1-phenyl-2-thiohydantoin, and the like.

The thiazolone cyanine dye intermediates, utilized as the coreactants with the foregoing N-substituted 5-memberedketomethylene heterocyclic compounds, are characterized by the following general formulae:

wherein R2, R3, X and Z have the same values as above, R4 represents an aryl group of the benzene and naphthalene series such as phenyl, chlorophenyl, diphenyl or naphthyl, R5 represents either hydrogen or an acetylgrouh, R6 represents an alkyl or aralkyl group, e. g., methyl, ethyl, propyl, isopropyl, benzyl, p-phenethyl, and the like, R7 represents an alkyl group, e. g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, etc., and n represents a positive integer of from 1 to 3, and W represents the atoms necessary to complete a saturated nitrogenous heterocyclic nucleus, such as, for example, piperidine, pand y-pipecoline, Pytrolidine, mormdoline, tetrahydroquinoline, and the like.

The dyestufi intermediates illustrated by the Formulae a and c are prepared according to the method described in my copending application Serial No. 66,571, filed on December 21, 1948, and the intermediates illustrated by the second Formula I) are prepared according to the method described in capending application Serial No. 66,572., filed on December 21, 19.48.

The dyestufi intermediatesillustrated by Formula a. are, in general, obtained by treating a diarylformamidine, or its vinylog such as ,B-anilinoacrolein anil hydrochloride or. glutaconic aldehyde dianil hydrochloride, in the presence or an, acid condensing agent such as acetic anhydride or in the presence of a basic condensing agent such as. triethylamine. or piperidi-ne, with a thiazolone. cyanine dye.

The dyesturi intermediates illustrated by Formula b are obtained by treating a thiazolone cyanine dye. with: an aliphatic acid anhydride in the presence of a mixture of pyridine. and triethylamine followed by treatment with phosphorus pentasulfide to. yield the thioketone derivative. which; is subsequently alkylated with an alkylating agent in the usual way to yield the thioether derivative.

The dyestuff intermediates containing a terminal saturated heterocyclic nitrogenous ring nucleus are prepared by treating. a thiazolone cyanine dye. with a diarylformamidine or its vinylog in thev presence or absence of an aliphatic alcohol as. a diluent and in'the presence of a saturated heterocyclic nitrogenous compound; such as morpho1ine,, piperidine, tetrahydroquinoline, and the like.

The thiazolone cyanine dyes, utilized in pre- D e foregoing intermediates are characteri'zed by the following general formula:

wherein R2, R3,, X and Z have the same values as above, and are prepared according to the method described in my copending application Serial No. 786,814, filed November 18, 1947'. In general, the method consists of condensing a substituted thioamide with an a-halogen acetic acid. The compounds, in view of their ketomethylene configuration undergo keto-enol tautomerism, i. e., the keto group enolizes to form a hydroxyl group.

The following examples describe the preparation of some of the thiazolone cyanine dyeintermediates illustrated by Formulae a and b which are utilized in the preparation of the trinucl'ear cyanine dyes,

Example I A mixture of grams of diphenylformamidine,

5 grams of the thiazolone cyanine dye of the'following structure: r

and cc. of acetic anhydride was heated at 140 C. for minutes. After cooling; the product was precipitated with ether and purified .by dissolving in a small amount'of methanol followed by precipitation with ether. A yield of 5.9 grams of yellow green crystals, having a melting point A mixture of 75 cc. of pyridine, 15 cc. of propionic anhydride, 15 cc. of triethylamine, and 15 grams of thiazolone cyanine dye of the following structure:

l CH3 was heated at 120 C. for 30 minutes. Fifteen grams of phosphorus pentasulfide were added in portions and the reaction mixture stirred at 120 answer):

C. for 30 minutes. The product was isolated by A mixture of cc. of pyridine, 10 cc. of propionic anhydride, 10 cc. of triethylamine, and 13 grams of the thiazolone cyanine dye of the following structure:

s H2C-S on l=....

N i A N I flflfi was heated with stirring at 120 C. for 20 minutes. During. the course of 10 minutes, a total of 10 grams of phosphorus pentasulfide was added in portions at 120 C. After an additional 10 minutes heating and stirring at 120 C., the mixture was poured into cold water and stirred until the first formed oil solidified. The crude product was stirreclwith 300 cc. of a 1% aqueous solution of sodium hydroxide and purified by boiling out with isopropanol. There was obtained 10.2'grams of yellow powder which decomposes at about 200 C.

A mixture of 9.3 grams of the yellow powder and 10 grams of methyl p-toluenesulfonate was fused at- C. for 1 hour. After cooling, the product wa washed with ether and dissolved in 10 cc. of warm acetone. The final product was precipitated as the iodide, by adding 25 cc. of methanol containing 20% sodium iodide. product was washed with water and purified by boiling out with isopropanol. A yield of 4.3 grams of a product melting at 225-228 C. was obtained;

Example IV C2115 n CH3-S =C CHr-(E OH:

\ I i I (EaHs A mixture of 15 cc. 'of pyridine, 2 cc. of propionic anhydride, 2 cc. of triethylamine, and 2.0 grams of the thiazolone cyanine dye of the following structure:

The i was heated at 120 for 3.minutes. There were then added 2 grams of phosphorus pentasulfide Emmple and the mixture heated at 115 6: for 15 minutes. 8 A dark red. oil was precipitated: by the addition jf of 100. cc. of water and washed with water by s=JJ o-on 0=t J=CH-C decantation. The product was fused with. 3 cc.

of methyl sulfate at 95 C. for 10 minutes to H yield 4.5 grams of a yellow-orange solution which a 0 (1,11 may be employed in dye synthesis.

Example V Br CH CH A mixture of 0.35 gram of 3-allylrhodanine, 0.8 5 gram of the intermediate of Example I, 50 cc. of H2 methanol and' 0.5- cc. of triethylamine was heated 1- at=reflux for-5 minutes. The crude dye was boiled out wtih methanol and finally crystallized from pyridine. A yield of 1.25 grams of a product melting above 295 C. was obtained. The absorption maximum of this dye in a methanol solution is 610 mu. I

Example VIII A mixture of 0.5 grams of the product of Ex- CzHs ample III, 0.3 gram of fi-anilinoacrolein anil hydrochloride, 10 cc. of methanol, and 0.5 gram & g OH I of piperidine was heated at reflux for 5 minutes. T The reaction mixture, was, poured into 60' cc. of N N I water containingv 1 gram of potassium iodide. $H2CH=CHL The crystals were separated and purified by boil- 2H5 ing out with i'sopropyl alcohol. A yield of 0.4 gram, of a product having a melting point of B 270-271 C. was obtained. A methanol solution r 1 3? compwnd has an absorptlm maxlmum A mixture of 0.35 gram of 3*-allylrhod'anine, 1.03 grams of the intermediate of Example III, Example; VI cc. of methanol and 1 cc. of triethylamine was GET-CH2. S H2O N-GH=C-H'-CH.=GHCH=C,-S cnrcfiz 0:6 t=cn c i \N/ V a lzHs A mixture of 2.85 grams of glutaconaldehyde heated at reflux for 15 minutes: After cooling, dianil hydrochloride, 4.3 grams of the compound the dye was separated and purified byboiling out of Example III, 1 cc. of piperidine and- 50 cc. with methanol. A yield of 0.5 gram of a product of methanol was heated at reflux for 30 minutes: melting; at FIB-175 C; was obtained. The absorp- The reaction mixture was poured into 300 cc. of tion maximum in methanol is 594 m When the water containing 5 grams of potassium iodide; dye is incorporated; intoa photographic'emulsion The precipitated product was filtered and boiled the sensitizationmaximum is 650 m out with isopropyl alcohol. A yield of 3.7 grams of a compound having a melting point of 195-198" Example IX C. was obtained. A methanol solution of the on -c o-oH=oH-oH=0s product has an absorption at 624 mu. 3 T

The anions of the foregoing thiazolone cyanine O:

dye salts may be replaced by other anions, such. as: iodide, thiocyanate or perchlorate; ions by treating an alcohol solution of the halogen salt 0 with an aqueous or aqueous-alcohol solution containing a sodium or potassium salt of the desired anion.

The following examples describe in detail the A mixture of 0.6 gram of the intermediate of improved and simplified method of preparing tri- Example -2 gram of 3-methy1 -p y pyra nuclear cyanine dyes from the foregoing thiazo- Zolone, 20 cc of methanol, and 1 cc. oftriet y lone cyanine dye intermediates, but it is to be amine washeatedat reflux for'l0 minutes. The understood that they are given merely for the purvery slightly-soluble dye was filtered ofi and puripose of illustration and are not. to be construed fi'edby. boiling out with methanol. A yield of 0.6' as limitative. A 7 gram of the purifiecfdye. wasobtalned;

Example X A mixture of 1.2 grams of the intermediate of Example VI, 0.5 gram of 3-ally1-I-methyI-Z thiQ- A mixture of 0.5 gram of the product ofExample II, 0.2 gram of 3-allylrhodanine, 15 cc. of isopropyl alcohol, and 0.5 cc. of triethylarnine was heated at reflux for 10 minutes. The dye separated on cooling and was purified by boiling out with isopropyl alcohol. A yield of 0.4 gram of the dye was obtained. The absorption maximum of a methanol solution is 583 Ill 1.. When incorporated in a photographic emulsion the sensitization is at 640 m While the present invention has been described in considerable detail with reference to certain preferred procedures and materials employed, it is understood that the improved process of preparing trinuclear cyanine dyes is not limited thereto, and that numerous variations and modifications described in the foregoing specification may be made as, for example, the dyes which contain a thioketone group in the terminal 5-membered heterocyclic nitrogenous nucleus, as illustrated in Examples '7, 8, 10 and 11 inclusive, may be further treated with a quaternizing compound such as methyl iodide. The quaternized compound is then condensed under reflux conditions with a cyclammonium base or salt of the type used in cyanine dyes, such as Z-methylbenzothiazole ethiodide and the like, having a reactive methyl group in oc-DOSitiO-Il to the nitrogen atom thereof, in the presence of a basic condensing agent such as pyridine. In the first reaction (alkylation), the trinuclear dye is modi- V fied to the extent that the nitrogen atom in the 3-position of the oxazoledio-ne, hydantoin or rhodanine ring is quaternized and the sulfur atom in the 2-position is converted to a thioether group. In the second reaction(condensation), the alkylated trinuclear cyanine dye is condensed with a cyclammonium base or salt whereby symmetrical tetranuclear and new unsymmetrical tetranuclear cyanine dyes are obtained. Accordingly, the scope of my invention 15 139.138 limited solely by the appended claims.

t aCM I I claim: 1. Trinuclear cyanine dyestuffs of the class consisting of compounds having the following 15 formulae:

wherein m. represents a positive integer of from 1 to-3, R. is selected from the class consisting of hydrogen and lower alkyl, R1 and R2 are selected from the class consisting of alkyl, allyl, aryl and aralkyl groups, R3 is selected from the class conr 'Sisting of lower alkyl, lower hydroxyalkyl, lower alkoxyalkyl, aryl of the benzene and naphthalene series, and aralkyl groups, X represents an acid radical, Y represents the residue of a B-membered heterocyclic nitrogenous ring system, and Z represents the residue of a heterocyclic nucleus of the type used in cyanine dyes. v

2. A trinuclear cyanine dyestuil having the formula:

3. A trinuclear cyanine dyestufi having the formula:

tHs. V I 0 11 5. A process for the production of trinuclear cyanine dyestuffs which comprises treating in the presence of a basic condensing agent a .5-membered ketomethylene heterocyclic compound of the formula:

i" i I ICO-bHl It with a thiazolone cyanine dye intermediate characterized by a formula selected from the class consisting of the following formulae:

ll it X wherein R1 and 'R2 represent a member selected from the class consisting of alkyl, allyl, aryl, and aralkyl groups, R3, represents a member selected from the class consisting of lower alkyl,

lower "hydroxyalkyl, lower alkoxyalkyl, aryl of the benzene and naphthalene series, and aralkyl groups, R4 represents an aryl group, R5 represents a member selected from the class consisting of hydrogen and acetyl group, R6 represents a member selected from the class consisting of alkyl and aralkyl groups, R7 represents an allzyl group, n represents a positive integer of from 1 to 3, W represents the atoms necessary to complete a saturated heterocyclic nitrogenous ring system selected from the class consisting of piperidine,

,6- and 'y-pipecoline, pyrrolidine, morpholine, and

which :comprises treating in the presence of a basic condensing agent a thiazolone cyanine dye intermediate of the formula:

OHa

with 3-allylrhodanine.

7. The process for the production of a trinuclear cyanine dyestufi characterized by the following formula:

which comprises treating in the presence of a basic condensing agent a thiazolone cyanine dye intermediate of the formula:

with S-allylrh-odanine.

8. The process for the production of a trinuclear cyanine dyestufi characterized by the following formula:

which comprises treating in the presence of a basic condensing agent a thiazolone cyanine dye intermediate of the formula:

with 3-methyl-l-phenyipyrazolone.

THOMAS R. THOMPSON.

No references cited. 

1. TRINUCLEAR CYANINE DYESTUFFS OF THE CLASS CONSISTING OF COMPOUNDS HAVING THE FOLLOWING FORMULAE: 